A data center is a facility that houses computer systems and various networking, storage, and other related components. Data centers may, for example, provide computing services to businesses and individuals as a remote computing service or to provide “software as a service” (e.g., cloud computing). To facilitate utilization of data center resources, virtualization technologies may allow a single physical computing machine to host one or more instances of virtual machines that appear and operate as independent computer machines to a connected computer user. With virtualization, the single physical computing device can create, maintain, or delete virtual machines in a dynamic manner.
Some virtualization technologies are capable of providing virtual resources that span two or more physical resources, such as a single virtual machine with multiple virtual processors that spans multiple distinct physical computing systems. As another example, virtualization technologies may allow data storage hardware to be shared among multiple users by providing each user with a virtualized data store that may be distributed across multiple data storage devices, with each such virtualized data store acting as a distinct logical data store that provides users with the illusion that they are the sole operators and administrators of the data storage resource.
Operators of data centers that provide different types of virtualized computing, storage, and/or other services typically use standard networking protocols to receive customer requests and transmit responses to such requests using commodity network hardware such as network interface cards (NICs). Despite recent advances in virtualization technology, many networking-related properties of virtual servers are typically managed at the level of individual physical network interface cards.